Air transporting arrangement

Abstract

An arrangement for transporting air with the aid of so-called electric ion wind with an air flow duct (1) in which a corona electrode (K) and a target electrode (M) are arranged in mutually axial spaced relationship, with the target electrode located downstream of the corona electrode. The corona electrode and the target electrode are each connected to a respective terminal of a d.c. voltage source (3), the voltage of which is such as to engender an air-ion generating corona discharge at the corona electrode. Arranged opposite the corona electrode on, or closely adjacent the wall of the air flow duct (1) are electrically conductive surfaces (4), which are connected to a potential which lies between the potential of the corona electrode (K) and the potential of the target electrode (M) and which is selected so that the potential difference between the electrically conductive surfaces (4) and the corona electrode (K) is as large as possible without any substantial part of the corona current passing to the surfaces (4). When the corona electrode has a plurality of mutually parallel and mutually adjacent wire-like electrode elements, further electrically conductive surfaces (5) may be provided between mutually adjacent wire-like electrode elements of the corona electrodes. These further electrically conductive surfaces (5) are electrically connected to the first mentioned electrically conductive surfaces (4) and extend parallel with the electrode elements and with the longitudinal extension of the duct (1).

We claim: 
     
       1. An arrangement for generating an air flow, with the aid of an electric ion wind, of a predetermined direction through an air flow duct with a rectangular cross-section and four duct walls, comprising a corona electrode consisting of at least two wire-like, mutually parallel electrode elements extending across said air flow duct substantially parallel to two mutually opposite duct walls and substantially in a common cross-sectional plane of the air flow duct; a target electrode located in the air flow duct axially spaced from and downstream of the corona electrode as seen in the direction of said air flow; a d.c. voltage source having one terminal connected to the corona electrode and another terminal connected to the target electrode, the distance and potential difference between corona electrode and target electrode being such that an air-ion generating corona discharge will occur at the corona electrode elements; and at the location of said corona electrode, first electrically conductive surfaces arranged closely adjacent inner surfaces of the mutually opposite duct walls which extend parallel with the wire-like electrode elements of the corona electrode, and other electrically conductive surfaces extending parallel with said first electrically conductive surfaces and located between said wire-like electrode elements of the corona electrode in a manner such that at most two corona electrode elements are located between each pair of two mutually adjacent first and other electrically conductive surfaces; and that said first as well as said other electrically conductive surfaces are connected to a common potential between a potential of the corona electrode and a potential of the target electrode. 
     
     
       2. An arrangement as claimed in claim 1, wherein additional electrically conductive surfaces are connected to said common potential and are provided closely adjacent the inner surfaces of the mutually opposite duct walls which extend perpendicular to the wire-like electrode elements of the corona electrode; said additional electrically conductive surfaces having a ring-shaped configuration and encircling the ends of the wire-like corona electrode elements at a distance therefrom. 
     
     
       3. An arrangement as claimed in claim 1, wherein said common potential is earth potential. 
     
     
       4. An arrangement as claimed in claim 1, wherein said first and other electrically conductive surfaces extend both upstream and downstream of said cross-sectional plane of the air flow duct containing said corona electrode. 
     
     
       5. An arrangement as claimed in claim 1, comprising a screening electrode arranged upstream of said corona electrode and connected to essentially the same potential as the corona electrode, said screening electrode being configured so as to exhibit a smaller screening effect at the ends of said wire-like electrode elements of the corona electrode than at the central portion of said electrode elements.